An appraisal on biochar functionality and utility in agronomy
Today, the exploitation of fossil fuels worldwide has led to rising greenhouse gas emissions, especially CO2, air pollution, and global warming. These environmental issues have recently increased global attention for alternative energy supply, especially from renewable resources. Any form of renewable carbon in waste plant biomass and animal manure, as well as organic matter in industrial effluents, municipal solid wastes, sewage sludge, and other waste materials can be transformed to hydrocarbon-based biofuels. Biofuels, especially those produced from agricultural crop residues, forestry biomass, algae, energy crops, and new plants for photosynthesis, use oil-seed plants and are considered carbon-neutral because of the CO2 emitted from their combustion. In other words, the energy content in biofuels is derived from biological carbon fixation. This chapter aims to throw light on pyrolysis and gasification as the technologies to produce biochar from a broad range of feedstocks. A special emphasis of this chapter is on the agronomic applications of biochar, especially in carbon sequestration, soil amelioration, crop improvement, and heavy metal adsorption.